Dozens of parliamentary questions about Indigenous affairs have been ignored by the Federal Government for months, prompting accusations it does not take the policy area seriously.

Key points: Government has not answered over 50 questions

Government has not answered over 50 questions Malarndirri McCarthy says it shows the Government is not serious about Indigenous issues

Malarndirri McCarthy says it shows the Government is not serious about Indigenous issues Rachel Siewert has condemned the lag

The Prime Minister's Department fronted a Senate committee hearing in late October and was given more than 50 questions to respond to at a later date.

But three months on, the public service's central agency appears not to have answered a single one.

"I think the delay by the Government in not answering these questions is really about hiding the truth behind what they're doing," NT Labor Senator Malarndirri McCarthy said.

"This is an arrogant Government that does not want to share, or care about, its process in Indigenous affairs.

"It just shows that they're not serious in relation to Indigenous issues in this country."

Questions from Coalition, Labor and Greens senators are marked "unanswered" and "overdue" on Parliament's website.

Some of the of unanswered questions as of January 25, 2018. ( ABC News )

The highest number of queries relate to a troubled Indigenous work-for-the-dole scheme, along with Constitutional change, including the rejected Uluru Statement.

In a statement, a spokesman for the department said it hoped to respond to the senators' questions next week.

"The department is working to provide responses to all outstanding questions on notice as quickly as possible."

Greens Senator Rachel Siewert — who also has a range of questions unanswered — condemned the lag.

"For such a well-resourced department, it is concerning that the Department of the Prime Minister and Cabinet has not answered a single question asked in October last year," she said.

"The questions asked are important and should be answered, particularly on Aboriginal issues where there are many pertinent issues that need addressing."

The agency snubbed one question about procurement, saying the topic should have been directed to the Finance Department.

An enquiry about the Elders Council of Tasmania is marked as "answered", but the answer is blank.

The department is responsible for most Aboriginal and Torres Strait Islander government programs, and the majority of its 2,300 staff are focussed on Indigenous affairs.

The department took about 100 questions on non-Indigenous issues, of which about three-quarters have been responded to.

Senate estimates hearings generally occur three times each year, where ministers and senior public servants are quizzed about their portfolios.

Senators can also ask so-called questions on notice, which are either asked in person, or sent after a hearing.

These questions are generally responded to in about a month.