Peters has said he was "very concerned", but has steered clear of the term "ethnic cleansing".
New Zealand recently announced an additional $2.5 million in aid to support the Rohingya crisis, bringing the total to $4m in New Zealand aid to help those caught up in the humanitarian emergency.
Tabuteau said that Tin gave him a commitment to bring the situation to a peaceful resolution.
"The minister said to me that they're concluding talks with Bangladesh on the return and resettlement process for a lot of the displaced people. They're now talking with Bangladesh in terms of taking back a huge proportion of [displaced people]."
Tabuteau said it was hard to say how many would return because the MOU talks had yet to conclude, but he estimated "at least half, or more than half".
"We went over to look them in the eye to communicate our concern, and thankfully when we sat down with him in the bilateral, that was exactly his commitment."
Myanmar has been heavily criticised for alleged human rights abuses and atrocities including rape.
Tabuteau was not given a commitment on when the MOU would be signed, saying the sheer volume of numbers complicated the issue - but he did not think Tin's commitment was an empty promise.
Tabuteau also had broader discussions with Myanmar state counsellor Aung San Suu Kyi, who gave him the same commitment for peaceful Rohingya resettlement.
He said the ASEM meetings discussed a broad range of issues, including keeping pressure on North Korea over its military testing, and committing to sustainable development goals.
Tabuteau said New Zealand also signed agreements with Myanmar about New Zealand's support for efficient and transparent governance in Myanmar's newly democratic institutions.
"My impression is they are making progress, and that is why New Zealand is there to help with their economic and government transitions."
He also held bilaterals with foreign delegations from many countries including Poland, Belgium, Norway, and Sweden.
