Speaking at a techUK event, Onwurah said: "We haven't seen the same transformation in the public sector as in the private sector. The prize of digital government glitters before us. Only through digital can you cut costs and improve services."
The Labour party's manifesto is likely to include proposals on digital government in three main areas: digital inclusion, data ethics and civil service skills, she told attendees.
Labour will focus on improving broadband coverage, getting more people online and giving citizens more control over their data as part of a wider 'digital inclusion' drive if it wins power in the May 2015 general election, Onwurah said.
The party wants to improve digital services in local government by setting up 'local digital factories' to build and share reusable platforms. Labour will also set up initiatives to improve civil servants digital skills, Onwurah added.
She said: "In future all government will be digital. Public servants need to understand that and be motivated and inspired to use digital to improve all our lives. The civil service has unique challenges around culture and leadership, but we need to meet them."
The proposals will be based on the 'digital government review' commissioned by Labour in December 2013, which came back with 35 recommendations last November, based on over 2,000 submissions and responses.
"We are studying the report in detail now to see what should go into the manifestobut there were three key recommendations we are considering," Onwurah said.
"GDS [the Government Digital Service] was barred from working with local government, but many local authorities don't have the scale to rise to the challenge of digital. So we plan to build 'local digital factories' to enable reuse to help communities, councils, and businesses", she said.
Although Labour will continue many of the policies on digital government pursued by the current administration, Onwurah criticised the current government's policies on data sharing and the 25 'digital exemplars'.
"I'm very critical of this government's chaotic approach to data sharing. Look at care.data and HMRC plans to share our data. During his Hugo Young lecture, Ed Miliband said we want people to be able to access and own their data, not for it to be hoarded by the state."
She added: "GDS [the Government Digital Service] is a fantastic organisation, it brought great skills into the public sector, but my criticism of GDS, well really Cabinet Office ministers, is that they focused on transforming 25 headline-grabbing services rather than more valuable ones that can be used by everyone like planning, health and social care."
The manifesto is due out in April, after the dissolution of Parliament on 30 March, according to a Labour spokesman.
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