The High Court has reserved its decision on the validity of the Government's new Senate ballot laws passed in March.

Family First senator Bob Day brought a challenge against the laws, which he said make it more difficult for micro-party and independent senators to get elected by preventing elaborate preference deals.

Under the new laws, voters number parties one to six on the Senate ballot paper in order of their preferences above the line, or number individual candidates below the line.

The High Court was asked to consider three main questions, including whether the new laws for above and below the line voting set up more than one "method" of voting, putting it at odds with the Constitution.

Chief Justice Robert French noted the term "method" was introduced by Sir Alfred Deakin when the Constitution was being written to broaden the meaning.

The court spent some time discussing the definition of the term, and the three types of voting - first past the post, preferential party list above the line and a part compulsory preferential vote below the line.

The second question in the case related to the new provision to number at least six parties or groups above the line, and whether it was a direct election by the people.

The third issue concerned new rules about logos which Senator Day believes will discriminate against micro parties and independents.

Lawyers for Senator Day argued the changes were unconstitutional, and would disenfranchise 25 per cent of voters who do not vote for the major parties.

However, the Commonwealth argued they provided voters with greater control over their preferences, and that there was nothing in the constitution mandating a particular voting system.

No voting system mandated in Constitution: solicitor

Part of the case came down to the reading of sections of the constitution (seven and nine) which set up the powers for the Parliament to make laws about the election of senators.

Commonwealth solicitor Neil Williams told the court Senator Day's lawyers had misunderstood the Constitution and taken a very narrow view of the provisions.

On the concerns many voters who choose not to vote for the major parties would be disenfranchised, Mr Williams was also dismissive.

"There's no kind of system mandated in the Constitution," he told he court.

He said the only priority was that the voting system across the states was systematic.

Mr Williams also denied the ballot paper would be misleading.

The hearing has come at a critical time with the calling of a federal election imminent.

The Electoral Commission will be awaiting the outcome of the court's decision to know which ballot paper it needs to print, and politicians of all persuasions are wondering what preference arrangements they will need to make, whether the case is won or lost.

Prime Minister Malcolm Turnbull has previously said he was confident the laws would stand.

Senator Day said he hoped to hear a decision by the end of the week.