China on Friday revised up its nominal 2018 gross domestic product (GDP) by 2.1% to 91.93 trillion yuan, keeping it on track to achieving its goal of doubling the size of its economy by 2020 from 2010.

However, with the economy growing at its weakest pace in nearly three decades, the revisions could fuel scepticism about the credibility of Chinese data with some analysts suspecting authorities may be massaging the numbers to achieve Beijing's ambitious targets.

In a statement, the National Bureau of Statistics (NBS) said the change in the size of 2018 GDP will not significantly influence the calculation for the 2019 growth rate.

Yet some analysts suggest the nominal nudge may actually not be so nominal after all.

"Despite NBS stressing that the current round of revisions is the result of the census uncovering previously unrecorded activity, it's hard to ignore the fact that it will also help them meet official growth targets. In previous revisions real growth has almost always been revised upwards," said Julian Evans-Pritchard, Senior China Economist at Capital Economics, in a note.

Indeed, growth of about 6.2% is seen needed for the whole of this year and the next to meet the Communist Party's longstanding goal of doubling GDP and incomes in the decade to 2020. Such a rate of expansion would be a stiff ask given the 6.0% GDP growth logged in the third quarter - the slowest pace since 1992 - and with many analysts tipping the pace to slip below 6% in 2020.