Federal public servants will have their wages frozen for at least six months, while politicians are resisting a pay cut.

Assistant minister for the public service Ben Morton says commonwealth bureaucrats must help reduce the economic burden of COVID-19.

However, the public sector union says deferring wage rises for six months will save the budget just 0.058 per cent, not enough to outweigh the impact on tens of thousands of essential workers during the pandemic.

At the same time, Finance Minister Mathias Cormann has resisted strong calls for federal politicians to take a pay cut during the coronavirus crisis.

Senator Cormann has told the remuneration tribunal to institute the pay freeze, but no further.

“Right now, politicians are probably working harder than they ever have,” he told ABC radio.

“This is the most intense period in my working life that I am going through, and I think it's the same for most if not all of my colleagues.”