Kenya's opposition on Thursday called for demonstrations against the government after the ruling party moved to change the electoral law ahead of next month's re-run presidential poll.

After a case brought by opposition leader Raila Odinga, Kenya's Supreme Court annulled last month's presidential election, won by Uhuru Kenyatta, citing widespread mismanagement by the electoral commission.

Odinga said the proposed changes to the election laws were an attack on democracy and the constitution that must be resisted.

‘I call on this generation to resist, to rise up and resist. We are calling our people to action,’ he told a press conference in Nairobi.

‘Enough is enough. On Monday we will begin the demonstrations,’ Odinga said, reiterating a call for biweekly protests, every Monday and Friday.

‘Kenya is bigger than Uhuru Kenyatta and William Ruto,’ he said, referring to the country's deputy president.

This week, MPs from the ruling Jubilee Party introduced a bill seeking to resolve ‘ambiguity’ in the electoral law, a move opposition leaders say is designed to render legal some of the ‘irregularities and illegalities’ cited by the Supreme Court in its ruling.

- 'Changing the rules' -

James Orengo, a senior official in the opposition National Super Alliance (NASA), described the proposed constitutional amendments as an effort to change ‘the rules of the game’ ahead of the re-run, due on October 26.

‘They have reached a level where they feel that they can do anything, and change anything, including the constitution through the back door,’ Orengo said after leading a walk-out from Thursday's meeting with Jubilee and the Independent Electoral and Boundaries Commission (IEBC) in protest at the proposed changes.

The proposals were being debated during a special sitting of the Jubilee-dominated parliament on Thursday.

A copy of the Election Laws (Amendment) Bill, 2017, proposes reducing the powers of the chairman of the election commission, having manual tallying supersede electronically transmitted results and making tally forms count even if there is ‘a deviation from the requirements of the form’.

In August's vote, held under the current law, manual tallying served as the back-up to the electronic system put in place after Kenya's violently disputed 2007 election in which over 1,100 people died.

The Supreme Court had also criticised the lack of prescribed security features on tally forms in its ruling ordering the annulment.

Church groups joined the opposition in criticising the proposed amendments.

‘This is an unacceptable path since it will lead to mutilation of the constitution and weakening of institutions,’ said Archbishop Jackson Ole Sapit, head of the Anglican church in Kenya.

After the collapse of Thursday's talks, IEBC chairman Wafula Chebukati questioned the necessity of changing the law.

‘We don't need any other law to move forward with elections,’ he said.

Tensions are set to grow still further with the opposition's call for widespread anti-government demonstrations.

On Monday, a few hundred opposition supporters protesting outside the IEBC headquarters in central Nairobi were dispersed by police using tear gas and batons.