Barnaby Joyce failed to produce a final report when he was special envoy for drought assistance and recovery.
The former Nationals leader was appointed to the role when Scott Morrison reshuffled his ministry after being elevated to prime minister in August last year.
Drought Minister David Littleproud responded to Labor's order for documents in the Senate asking for Mr Joyce's final report from his work as drought envoy.
"The request for the former special envoy for drought assistance and recovery's report cannot be complied with as he did not prepare a final report and as such no document exists," he wrote.
Mr Joyce said in May he was disappointed the role was ditched after the coalition were re-elected.
He spent time visiting communities across eastern Australia grappling with the prolonged dry spell and provided advice to government.
The Senate order also asked for a final report from the Coordinator-General for Drought, Major General Stephen Day, but the government refused to release it on the grounds it was subject to cabinet deliberations.
Mr Littleproud said the government was concerned about deteriorating drought conditions facing farmers and communities across the country.
"The short-term outlook is not good, with rainfall deficiencies and warmer than average temperatures forecast for much of Australia over the next three months," he wrote.
Australian Associated Press