Efficiency battle: hybrid vs internal combustion

Electrification is a hot topic, as it has been for a while now, and there’s no denying or ignoring the impact it’s having on the market.

It seems every week there’s a new Chinese plug-in hybrid (PHEV) or mild hybrid (MHEV) version of a big-name model being added to the range and, unlike EVs (Tesla excluded), Aussies are lapping them up.

Hybrids and PHEVs were the only fuel types listed by the Federal Chamber of Automotive Industries as posting positive growth in the first six months of 2025, and as electrification technology gets better as well as cheaper, it makes a lot of sense.

But there are of course, plenty of people not ready to make the switch to hybrids, let alone EVs, standing by traditional petrol and diesel vehicles. So, this got us thinking; what are the most fuel-efficient internal combustion vehicles on the Australian market, and how do they compare to the equivalent hybrids?

And yes, we’re bundling mild hybrids in the internal-combustion camp since they can’t drive meaningful distances on electric power. PHEVs meantime are excluded on the grounds of being too far removed from reasonable comparison.

We’ll start with the hybrids since they’re technically the benchmark in this context.

It’s probably no great surprise the 2025 Toyota Yaris is the most fuel-efficient hybrid on this list.

In fact, it’s the world’s most fuel-efficient traditional hybrid, and it’s little wonder seeing as Toyota’s been refining the technology for decades now, plus the fact the sub-four-metre Yaris only weighs 1130kg.

It’s powered by a 1.5-litre three-cylinder hybrid system good for 85kW and drives the front wheels via a continuously variable transmission (CVT).

Using half a litre more than the pint-sized Yaris is its bigger, high-riding sibling, the 2025 Toyota Yaris Cross (and its upmarket Lexus LBX twin).

Mechanically identical to the city car but bigger and therefore heavier, the Yaris Cross/LBX twins both sport claimed combined fuel consumptions of 3.8L/100km.

Upping the power and performance ante but not giving much away in fuel consumption is the 2025 Toyota Corolla sedan with its 1.8-litre four-cylinder hybrid system good for 103kW and capable of returning 3.9L/100km.

Like its smaller stablemates, it drives the front wheels via a CVT and just edged-out the Hyundai i30 by means of its marginally bigger fuel tank (48L vs 47L) which theoretically means a superior fuel range since they supposedly use the same amount of fuel.

The 2025 Hyundai i30 Sedan Hybrid differs from its Toyota competition primarily via its six-speed dual-clutch automatic transmission and a slightly smaller 1.6-litre internal combustion engine.

It makes virtually the same power as the Corolla (104kW vs 103kW) and the two can’t be split on claimed fuel consumption at 3.9L/100km.

Using exactly same powertrain but bundling it into a compact SUV body is the 2025 Hyundai Kona Hybrid, of which there will soon be two new variants.

The Kona ranks bottom of the 3.9L/100km trio on account of its measly 37L fuel tank, which yields a theoretical fuel range of 949 litres compared to the i30’s 1205km and Corolla’s 1231km.

The 2025 Suzuki Swift is marketed as a genuine hybrid, but the fact of the matter is it’s not a hybrid – it’s a mild hybrid in the same ilk as the latest Toyota Prado and majority of current Audis.

Under the bonnet you’ll find a 1.2-litre three-cylinder petrol engine good for 61kW/107Nm, paired primarily to a five-speed manual transmission with a 12-volt integrated starter generator slotted in between.

Opt for the CVT version and fuel consumption increases to 4L/100km.

Something of a curveball some might not have seen coming, the second-most-fuel-efficient internal combustion model on the Australian market is the 2025 Audi Q5 35 TDI – a turbo-diesel medium SUV.

Said turbo-diesel displaces 1968cc across four cylinders and will supposedly return 4.8L/100km on the combined cycle with the help of a 12V mild hybrid system.

A victim of ADR 98/00 but still in local showrooms through clever stockpiling, the 2025 Suzuki Ignis doesn’t have any sort of mild hybrid tech or need fancy 95RON to return a sub-5L/100km consumption figure.

The base GL weighs just 865kg and is powered by a tiny 1.2-litre four-cylinder petrol engine that drives the front wheels through a CVT and uses 4.9 litres of 91RON per 100km.

At the opposite end of the spectrum, the 2025 Mazda CX-60 D50e Pure features a turbo-diesel 3.3-litre straight six outputting 187kW/550Nm, single-clutch automatic transmission and a rear-bias all-wheel drive system.

A 48V mild hybrid system contributes to an official combined fuel consumption of 5L/100km.

Rounding out this list is the 2025 Mazda2, all versions of which have claimed fuel consumptions of 5L/100km courtesy of a 1.5-litre four-cylinder petrol engine outputting 81kW/142Nm.

Drive is sent to the front wheels by a six-speed automatic transmission.

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