Mark Drakeford has said his relationship with the reappointed Welsh Secretary is “off to a reasonable start”.
Mr Drakeford also urged the new Prime Minister to use Labour’s already “costed plan” to tackle the energy crisis.
Sir Robert was first appointed to the role in July in the final days of Boris Johnson’s premiership, and has been kept on by Ms Truss despite initially backing her rival, Rishi Sunak, in the Tory leadership contest.
Speaking from a school in Pembrokeshire as the Welsh Government began the rollout of universal free school meals to all primary school children, Mr Drakeford said Sir Robert had “demonstrated he is keen to work with us”.
He told the PA news agency: “I’ve already met with Mr Buckland more times in a couple of months than I met with Mr (Simon) Hart in a year.
“But it’s very early days.
“We will look for a positive, constructive relationship with the new Government wherever that is possible.
“For that to be possible, they have to come to the table with us in a spirit of mutual respect, in which we recognise the things that are devolved, for which we are responsible, and the things which they retain responsibility for, in Whitehall.
“With a meeting later today we’re off to a reasonable start.”
Former Welsh secretary Simon Hart, who quit his Cabinet role amid mounting pressure for Mr Johnson to step down, repeatedly came to blows with the Welsh Government over devolved issues and constitutional matters.
Sir Robert, who is from Llanelli in South Wales, is the MP for South Swindon.
The choice to appoint another MP who represents an English constituency as Welsh Secretary has been criticised by Plaid Cymru.
In a statement, Sir Robert said: “It’s an honour and a privilege to be reappointed as the Secretary of State for Wales.
— UK Prime Minister (@10DowningStreet) September 6, 2022
“Wales has a huge part to play in our longer-term energy needs with potential for offshore wind, nuclear and renewable energy schemes.
“These are projects that create jobs and prosperity, help secure our energy future and deliver our net-zero targets.
“I am a proud Welshman and a proud unionist and want to see Wales prosper as a strong part of our successful United Kingdom.”
As pressure mounts on Ms Truss to reveal her plans to tackle the energy and cost-of-living crisis, Mr Drakeford said: “(Labour leader) Keir Starmer has already set out a detailed and costed plan as to how that could be done.
“The best thing of all she could do would be to take that plan off the shelf and put it to work.
“It would mean an energy cap freeze paid for through a windfall tax on the profits of companies who are making money hand over fist during this crisis.
“Not by borrowing money, not by putting it on people’s bills for another 20 years, but taking money from people who’ve got far more than they ever expected and putting that to work in the lives of people who don’t have enough.”